EnglishRebel
Retired Rebel Reefer
wmilas
I would bet you have an air leak somewhere. I noticed on one of the returns to my sump was putting out a lot of large bubbles but not the other (they are teed off the same return). I was checking all my joints on the suction side (I used a dropper with water to see if it was sucking it in but the Vaseline is an excellent idea). I couldn't find any and then it dawned on me that it must be in the return piping as it was only on one side. Now you would think that a gravity return would show a leak by dripping water, but no. I tightened the union on that return and the bubbles stopped. Apparently the water rushing down through the pipe created a suction that must have pulled the o-ring off its seat.
So moral of this is don't just check the suction side of the pump, check your return piping too.
I would bet you have an air leak somewhere. I noticed on one of the returns to my sump was putting out a lot of large bubbles but not the other (they are teed off the same return). I was checking all my joints on the suction side (I used a dropper with water to see if it was sucking it in but the Vaseline is an excellent idea). I couldn't find any and then it dawned on me that it must be in the return piping as it was only on one side. Now you would think that a gravity return would show a leak by dripping water, but no. I tightened the union on that return and the bubbles stopped. Apparently the water rushing down through the pipe created a suction that must have pulled the o-ring off its seat.
So moral of this is don't just check the suction side of the pump, check your return piping too.